Metalloproteinases are enzymes present in the body which are often involved in the degradation of connective tissue. While some connective tissue degradation is necessary for normal functioning of an organism, an excess of connective tissue degradation occurs in several disease states and is believed to be attributable, at least in part, to excess metalloproteinase. It is believed that metalloproteinases are at least implicated in periodontal disease, corneal and skin ulcers, rheumatoid arthritis and the spread of cancerous solid tumors.
These diseases generally occur in areas of the body which contain a high proportion of collagen, a particular form of connective tissue. An examination of patients with these diseases of connective tissue has revealed an excessive breakdown of the various components of connective tissues, including collagen proteoglycans and elastin. Therefore, it has been deduced that an excessive concentration of a particular metalloproteinase, for example-collagenase, proteoglyconuse, gelatinase, and certain elastases, may cause or exacerbate the connective tissue destruction associated with the aforementioned diseases.
In the normal state, the body possesses metalloproteinase inhibitors which bind to metalloproteinases to effectively prevent these enzymes from acting on their connective tissue substrates. Specifically, in a healthy organism, metalloproteinase inhibitors are present in concentrations sufficient to interact with metalloproteinases to an extent which allows sufficient quantities of metalloproteinase to remain active while binding the excess metalloproteinase so that the connective tissue damage seen in the various diseases does not occur.
It is postulated that one immediate cause of the connective tissue destruction present in the foregoing disease states is an imbalance in the relative metalloproteinase/metalloproteinase inhibitor concentrations. In these situations, either due to an excessive amount of active metalloproteinase or a deficiency in the amount of active metalloproteinase inhibitor, the excess metalloproteinase is believed to cause the connective tissue degradation responsible for causing or exacerbating the disease. It is postulated that, by treating persons with connective tissue diseases with metalloproteinase inhibitors, the degradative action of the excess metalloproteinase may be curtailed or halted. Therefore, particular metalloproteinase inhibitors of specific interest to the present inventors are collagenase inhibitors because it is believed that these inhibitors would be pharmaceutically useful in the treatment or prevention of connective tissue diseases.
The existence of metalloproteinase and metalloproteinase inhibitors has been discussed in the scientific literature. For example, Sellers et al., Biochemical And Biophysical Research Communications 87:581-587 (1979), discusses isolation of rabbit bone collagenase inhibitor. Collagenase inhibitor isolated from human skin fibroblasts is discussed in Stricklin and Welgus, J. B. C. 258:12252-12258 (1983) and Welgus and Stricklin, J. B. C. 258:12259-12264 (1983). The presence of collagenase inhibitors in naturally-occurring body fluids is further discussed in Murphy et al., Biochem. J. 195:167-170 (1981) and Cawston et al., Arthritis and Rheumatism, 27:285 (1984). In addition, metalloproteinase inhibitors are discussed by Reynolds et al. in Cellular Interactions, Dingle and Gordon, eds., (1981). Although these articles characterize particular, isolated metalloproteinase inhibitors and discuss, to some extent, the role or potential role of metalloproteinases in connective tissue disease treatment and speculate on the ability of metalloproteinase inhibitors to counteract this destruction, none of these researchers had previously been able to isolate a portable DNA sequence capable of directing intracellular production of metalloproteinase inhibitors or to create a recombinant-DNA method for the production of these inhibitors.
Surprisingly, the present inventors have discovered a portable DNA sequence capable of directing the recombinant-DNA synthesis of metalloproteinase inhibitors. These metalloproteinase inhibitors are biologically equivalent to those isolated from human skin fibroblast cultures. The metalloproteinase inhibitors of the present invention, prepared by the recombinant-DNA methods set forth herein, will enable increased research into prevention and treatment of metalloproteinase-induced connective tissue diseases. In addition, the metalloproteinase inhibitors of the present invention are useful in neutralizing metalloproteinases, including the excess metalloproteinase associated with disease states. Therefore, it is believed that a cure for these diseases will be developed which will embody, as an active ingredient, the metalloproteinase inhibitors of the present invention. Furthermore, the metalloproteinase inhibitors of the present invention are capable of interacting with their metalloproteinase targets in a manner which allows the development of diagnostic tests for degradative connective tissue diseases using the newly discovered inhibitors.
The recombinant metalloproteinase inhibitors discussed herein interact stoichiometrically (i.e., in a 1:1 ratio) with their metalloproteinase targets. In addition, these metalloproteinase inhibitors are heat resistant, acid stable, glycosylated, and exhibit a high isoelectric point.
The present invention relates to metalloproteinase inhibitors and a recombinant-DNA method of producing the same and to portable DNA sequences capable of directing intracellular production of the metalloproteinase inhibitors. Particularly, the present invention relates to a collagenase inhibitor, a recombinant-DNA method for producing the same and to portable DNA sequences for use in the recombinant method. The present invention also relates to a series of vectors containing these portable DNA sequences.
One object of the present invention is to provide a metalloproteinase inhibitor, which can be produced in sufficient quantities and purities to provide economical pharmaceutical compositions which possess metalloproteinase inhibitor activity.
An additional object of the present invention is to provide a recombinant-DNA method for the production of these metalloproteinase inhibitors. The recombinant metalloproteinase inhibitors produced by this method are biologically equivalent to the metalloproteinase inhibitor isolable from human skin fibroblast cultures.
To facilitate the recombinant-DNA synthesis of these metalloproteinase inhibitors, it is a further object of the present invention to provide portable DNA sequences capable of directing intracellular production of metalloproteinase inhibitors. It is also an object of the present invention to provide cloning vectors containing these portable sequences. These vectors are capable of being used in recombinant systems to produce pharmaceutically useful quantities of metalloproteinase inhibitors.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned from practice of the invention. The objects and advantages may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the present invention, metalloproteinase inhibitors are set forth, which are capable of stoichiometric reaction with metalloproteinases. These metalloproteinase inhibitors are remarkably heat resistant, acid stable, glycosylated, and exhibit a high isoelectric point. Furthermore, these metalloproteinase inhibitors are biologically equivalent to those inhibitors isolated from human skin fibroblast cultures.
To further achieve the objects and in accordance with the purposes of the present invention, as embodied and broadly described herein, portable DNA sequences coding for metalloproteinases inhibitors are provided. These sequences comprise nucleotide sequences capable of directing intracellular production of metalloproteinase inhibitors. The portable sequences may be either synthetic sequences or restriction fragments (xe2x80x9cnaturalxe2x80x9d DNA sequences). In a preferred embodiment, a portable DNA sequence is isolated from a human fibroblast cDNA library and is capable of directing intracellular production of a collagenase inhibitor which is biologically equivalent to that inhibitor which is isolable a human skin fibroblast culture.
The coding strand of a first preferred DNA sequence which has been discovered has the following nucleotide sequence (SEQ ID No: 5):
The nucleotides represented by the foregoing abbreviations are are set forth in the Detailed Description of the Preferred Embodiments.
A second preferred DNA sequence has been discovered which has an additional nucleotide sequence 5xe2x80x2 to the initiator sequence. This sequence, which contains as the eighty-second through four-hundred-thirty-second nucleotides nucleotides 1 through 351 of the first preferred sequence set forth above, has the following nucleotide sequence (SEQ ID No: 6):
A third preferred DNA sequence which incorporates the 5xe2x80x2 region of the second preferred sequence and the 3xe2x80x2 sequence of the first preferred sequence, has the following nucleotide sequence (SEQ ID No: 7):
To facilitate identification and isolation of natural DNA sequences for use in the present invention, the inventors have developed a human skin fibroblast cDNA library. This library contains the genetic information capable of directing a cell to synthesize the metalloproteinase inhibitors of the present invention. Other natural DNA sequences which may be used in the recombinant DNA methods set forth herein may be isolated from human genomic libraries.
Additionally, portable DNA sequences useful in the processes of the present invention may be synthetically created. These synthetic DNA sequences may be prepared by polynucleotide synthesis and sequencing techniques known to those of ordinary skill in the art.
Additionally, to achieve the objects and in accordance with the purposes of the present invention, a recombinant-DNA method is disclosed which results in microbial manufacture of the instant metalloproteinase inhibitors using the portable DNA sequences referred to above. This recombinant DNA method comprises:
(a) preparation of a portable DNA sequence capable of directing a host microorganism to produce a protein having metalloproteinase inhibitor activity, preferably collagenase inhibitor activity;
(b) cloning the portable DNA sequence into a vector capable of being transferred into and replicating in a host microorganism, such vector containing operational elements for the portable DNA sequence;
(c) transferring the vector containing the portable DNA sequence and operational elements into a host microorganism capable of expressing the metalloproteinase inhibitor protein;
(d) culturing the host microorganism under conditions appropriate for amplification of the vector and expression of the inhibitor; and
(e) in either order:
(i) harvesting the inhibitor; and
(ii) causing the inhibitor to assume an active, tertiary structure whereby it possesses metalloproteinase inhibitor activity.
To further accomplish the objects and in further accord with the purposes of the present invention, a series of cloning vectors are provided comprising at least one of the portable DNA sequences discussed above. In particular, plasmid pUC9-F5/237P10 is disclosed.
It is understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawing, which is incorporated in and constitutes a part of this specification, illustrates one embodiment of the invention and, together with the description, serves to explain the principles of the invention.